PDCD1LG2 and acute myeloid leukemia: Briefly, all these B7-positive cases shared the presence of B7.2, PD-L1, or PD-L2 but had a rather heterogeneous expression of ICOS-L, B7-H4, and B7-H3, ligands that are likely involved in fine-tuning the immune escape process across different AML subtypes.